Warm Ups:
Its always a good idea to warm up your voice before you sing. Today I'm going to list some warm up ideas. 

Lip trill:lip trill is like blowing bubbles in the water, except there's no water.Do this for the octave of C, and go as high as you can go.

Hum: Hum the octave of C and only go as high as you are comfortable. *REMEMBER to drink lots of water before and after you sing. This helps to keep you hydrated and prevents your voice from straining. 

Sing Vowels: Go up and down octaves and sing vowels (can include a consonant at the beginning) Ex/ Ahh, nooo, laaa, zeee, etc.

*Never give up. It can be hard at the beginning but you'll get the hang of it!